Generally, nonwoven fabric, after manufacturing, is wound in rolls to be stored in a form of a web roll of nonwoven fabric. Thereafter, in another process, the nonwoven fabric is fed out from the web roll and used. At the time of winding the nonwoven fabric, the nonwoven fabric is subject to tension. Consequently, the nonwoven fabric which has been wound is compressed in the thickness direction and its bulkiness decreases. For this reason, the method being for recovering bulkiness of the nonwoven fabric has been proposed in which hot air is blown to the surface of nonwoven fabric in the a direction normal to the surface to heat the nonwoven fabric (see [Patent Literature 1], for example).